Optical properties of Zinc Oxide/Polymer Nanocomposite

Semiconductor/polymer Nanocomposite materials have wide range of applications in optoelectronic industry in the fabrication of LEDs, Photo detectors, Displays etc due to their composition dependent electroluminescence (EL) and photoluminescence (PL) properties. ZnO/ PEG Nanocomposite materials are synthesized with varying ZnO, PEG ratio by laser ablation of pure Zn target in the aqueous solution of PEG at different concentrations. Synthesized Nanocomposite materials are characterized for UV-visible absorption, TEM, PL, Raman, XRD and EL spectroscopic techniques. With the increase of PEG concentrations in water surface plasmon resonance peak of ZnO increases, this reveals synthesis of more ZnO nanoparticles in the PEG matrix. TEM investigation illustrates synthesis of 2-3 nm sized quantum dots with very narrow size distribution. UV-visible absorption spectrum of quantum dots (QDs) synthesized in 30 ml water and 10 ml PEG (3:1 v/v) have small intensity of SPR peak corresponding to ZnO as compared to the peak corresponding to core transition electron. As the PEG concentration increases SPR peak corresponding to ZnO raises. It insures that PEG helps in the oxidation of Zn clusters to make ZnO. For the equal volume of water and PEG (1:1) ratio of SPR to inter band transition peak is maximum. Position of SPR peak also shifted towards right, which shows that particle size increases with the addition of PEG. TEM images shows that synthesized nanoparticles are 4-5 nm in size with very good monodispersity in size distribution. The particles are highly confined quantum dots (QDs) in nano-dimensional space. HRTEM image shows that several different planes of ZnO Nanocrystals.